There are some rules that make life with signals and slots easier and cover the most common reason for defective connections. If I forgot something please tell me. 1) Check the debug console output: When execution errors occur, the debug output can show you the reason. 2) Use the full signature of signal and slot: … Read more
Any time you add a new call to the Q_OBJECT macro, you need to run qmake again. The vtables issue you’re referring to is directly related to that. Just run qmake and you should be good to go assuming there are no other issues in your code.
//Is this possible in any way? //Q_PROPERTY(AnimalModel modelAnimals READ modelAnimals NOTIFY modelAnimalsChanged) Yes it is, didn’t you try? Of course, it will not be a AnimalModel but a AnimalModel *, but as long as the model inherits QAbstractListModel, that’s all you need. You don’t even need the NOTIFY part, as changes, internal to the model … Read more
Let’s use QStateMachine to make this simple. Let’s recall how you wished such code would look: Serial->write(“boot”, 1000); Serial->waitForKeyword(“boot successful”); Serial->sendFile(“image.dat”); Let’s put it in a class that has explicit state members for each state the programmer could be in. We’ll also have action generators send, expect, etc. that attach given actions to states. // … Read more
C++ answer (general answer) Consider a template class Derived with a template base class: template <typename T> class Base { public: int d; }; template <typename T> class Derived : public Base<T> { void f () { this->d = 0; } }; this has type Derived<T>, a type which depends on T. So this has … Read more
The problem here is that there are two signals with that name: QSpinBox::valueChanged(int) and QSpinBox::valueChanged(QString). From Qt 5.7, there are helper functions provided to select the desired overload, so you can write connect(spinbox, qOverload<int>(&QSpinBox::valueChanged), slider, &QSlider::setValue); For Qt 5.6 and earlier, you need to tell Qt which one you want to pick, by casting it … Read more
I wrote a guide to static linking and How to build Qt static with multiple compilers and keep it small (because it can get pretty big, especially for simple programs). You may also want to check out the BitRock installer, which is free for open source projects. In short, it turns out to be a … Read more
With Qt 5 and a C++11 compiler, the idiomatic way to do such things is to give a functor to connect: connect(action1, &QAction::triggered, this, [this]{ onStepIncreased(1); }); connect(action5, &QAction::triggered, this, [this]{ onStepIncreased(5); }); connect(action10, &QAction::triggered, this, [this]{ onStepIncreased(10); }); connect(action25, &QAction::triggered, this, [this]{ onStepIncreased(25); }); connect(action50, &QAction::triggered, this, [this]{ onStepIncreased(50); }); The third argument to … Read more
Widgets when they are visible for the first time call to be visible to their children, but since you are creating it afterwards they probably are not calling that method, a possible solution is to call the show method. void ChatWidget::displayChatAfterButtonPressed() { QLabel *lbl; lbl=new QLabel(this); lbl->setText(“Hello World 2”); lbl->show(); } comment: it seems strange … Read more
The proper way to do this is like this: LIBS += -L/path/to -lpsapi This way it will work on all platforms supported by Qt. The idea is that you have to separate the directory from the library name (without the extension and without any ‘lib’ prefix). Of course, if you are including a Windows specific … Read more